Tilting-hearth-tray furnace



' 45- turning them to a Patented` Apr. 3, 1928,

AUNITED STATES ALVIN D. KEENE, OF HANSFIELD, OHIO,

ASSIGNOR TO WESTINGHOUSE ELECTRIC MANUFACTURING COMPANY', A. CORPORATION OF PENNSYLVANIA.

` TILTING-HEARTH-TRAY FURNACE.

l Application led March 28, 1927. Serial No. 178,823.

invention relates to electric furnaces and more particularly vto furnaces of the rotary-hearth type.

In rotary-hearth furnaces wherein a plurality of pivotally mounted hearth trays are-moved through a furnace chamber and successively tilted at a predetermined point to effect the discharge of heated material therefrom, difficulty has been experienced in returning the hearth trays to the normal non-tilted position thereof, because of expansion and corrosion of the pivot joints which are exposed to the relatively high furnace temperature. f l5 An object of my invention, therefore, is to provide means positively engaging said tilting hearth trays to return the same to their normal position.

In practicing my invention, I provide an annular furnace chamber, a pluralityof tiltably-mounted hearth trays adapted to be moved therethrough,` and motor-controlled means for` engaging 'said trays successively to tilt the same to effect the discharge of 'heated material therefrom into a discharge V chute extending through a wall of the furnace.

An inclined surface is formed upon the wall of the furnace chamber,'which is beyond the dischargechute, in the path of movement of the front edge of the hearth trays so that', upon rotation of the hearths subsequent to discharge, the front edge of the tilted hearth rides upon the incline surface, and continued rotation forces the hearth edge up the incline to return the tray to a-horizontal position.

'-In the drawings, I Figure 1 isa view, in vertical section, of a furnace embodying my invention.

Fig. 2 is a development of a portion of the tray-tiltingmechanism, and i Figs. 3 and 4 are details, partly in section,

of the hearth trays and the means for rehorizontal position.

Referring to the drawings, an annular furnace, comprising top, bottomand side walls of'suitable refractory material, defines an annular furnace chamber 1.- wall of the chamber 1 is slotted alongfthe center line thereof, for a purpose hereinafter described.

The bottom Electrical resistors 2 are carriedv by the vwalls of the furnace chamber to effect the heating thereof.

An annular frame 6, resting upon a bearing surface 8 and pivoted at v10 co-axial with the furnace chamber, carries, peri thereof, a plurality of vertical stany ards 12 which extend -through the slot in the bottom wall of the furnace and terminate in hearth supports 14 within' the furnace chamber. Hearth trays 16 are pivotally secured to the supports 14 adjacent the outer edges thereof, to permit tilt-ing of the trays to discharge material therefrom. j

Rotation of the annular frame 6', in a clock'.- Wise direction, and the consequent movement of the hearths through the lfurnace cham-h ber is effected by a motor 20 cooperating, through suitable reduction gearing 22, shown diagrammatically, with an annular rack 24 secured to the annular frame 6.

A sand seal 26, one element of which -is carried by the vertical standards, and cooperating elements secured to the bottom wall of the furnace at the sides of the slot, prevent the influx of air into the furnace chamber. v

A discharge chute 30 extends through the si de wall of the furnace and co-operates with a bin or quench tank 32 so ositioned that, when a hearth tray is rotatedp into alignment with said discharge chute, the tray may be tilted and the material carried thereon-be d discharged into the tank.

Tilting of the trays 16 is accomplished by a motor 36 which rotates a drum 38, on the peripheral surface of which is la cam groove 40, shown more particularly in Figure 2. A.

rod 42 extends down through the furnace roof into the furnace chamber and adjacent a side wall thereof, with a lug orfnger on the upperend of the rod engaging the groove inthe drum 38 so that rotation of the drum causes a vertical movement ofthe rod-42.

'An angle 44 is pivoted, intermediate the ends thereof, to the lower extremity of rod 42. The horizontal arm of angle 44 extends beneath the edge of the hearth tray, and the vertical arm, carrying a roller 46,- or other friction-reducing means, bears against the side wall of the furnace chamber.

Since the tray-tilting mean;

herauy Y of '1s deemed unnecessary.

and control thereof constitute no partof the present invention, further description therevWithin the furnace chamber, upon the outer -wall thereof and adjacent the discharge chute, .is secured-a block 50, the -upper surface of which is inclined upwardly alignment with the discharge chute, whereupon the tilting motor is energized. Energization of the tiltingmotor causes the rotav 'tion of drum 38 which raises rod 42 and langle 44 to tilt .the tray to effectV the discharge of material therefrom into the chute 30. v 1

A complete rotation of drum 38 returns the angle 44 to its normal in Fig. 1. The tray 16, however, may remain in its tilted position, d ue to corrosion- .or expansion at the hinge, 1nl which event, upon further movement of thehearth, the lower edge of the tilted tray will ride upon the cam surface of'block 50 ,and be raised thereby to return vthe tra to a horizontal' of said `furnace .for engagingl said trays .when in tilted "normal position.

position.A By my invention, I have provided an effective and automatic means for returning Aa hearth tray to its normalhorizontal tion, whichovercomes the difficulties resultmg from expansion and corrosion 'otal mounting of the hearth tray.

Various modifications maybe made in myinvention without departing from the 's irit` and sco e thereof and I desire, there ore that on y such limitations shall be placedthereon as areimposed by the prior art, and -set forth in the appended claims. I claim as my invention: v

l. In a furnace, the combination annular furnace chamber, anda plurality of hearth trays mounted for movement through said chamber,

ythe discharge chute, in the'` [in the chamber thereof, .a

p'osition, as shown"- hearths, means with an of means for tilting said trays to effect the dischargeof -material therefrom, and means carried by a wall of said furnace for returning. said trays to a nontilte'd position.

2. In a rotary hearth furnace comprising a plurality of hearths mounted for movement therethrough, means for tilting saidhearths individually at apredetermined point to discharge material therefrom, and

meanskcarried by a wall of said furnace b eyond said discharge point for returning said tilted trays to normal position.

3. In an electric furnace, a moving hearth discharge opening through a wall of said furnace, means for -tilting said hearth to discharge heated4 material through said discharge opening, and

4Ameans carried by a wall of said furnace for returning said hearth to normal position subsequent to the said discharging operation.

4. In a'furnace, the combination with a furnace chamber, a plurality-lof hearths mounted for movement therethrough, and means for tilting said hearths to effect the discharge of material therefrom, ofautomatic means responsive to movement of said hearths through said furnace chamber for vreturning said hearths to normal, non-tilted position.- o

. 5.- In an electric furnace, the combination with a furnace chamber, a plurality of movable hearths therein, a discharge chute extending through a wall of said furnace, and

means for tilting-said hearths in sequence to discharge material carried thereby into said chuteof means carried by a Wall position to return them to an annular th'e'- discharge of material, therefrom, and

means for returning said trays to normal position subsequent to theA tilting thereof 'comprising an inclined surface carried by a -wall of said chamber and n the path of movement of saidl tilted trays.

In testimony subscribed my 1927.

whereof, I have hereunto .,LLvIN D. KEENE.

name this 22 day of March, 

